chevyz71man

I have a TBI 383. Has world torquer s/r heads on it, and cam specs are 112lsa with about .460 lift. Anyways, I installed a holley 670 TB and a walbro 190 pump. Right now the fuel pressure is set at 9psi according to my gauge, who knows if its right. When it is cold it wont idle for crap, sounds like a pro stock car. When it warms up though it idles fine, when my budd was following me he said when I got on it black smoke was shooting out the pipes.... This leads me to think its to rich, but how can it be to rich at 9psi?? The plugs are black and and full of soot to. Brian at TBI chips burned this prom for me. Anybody have problems running the holey 670?? I was thinking about putting a 350 injector pod on the holley base and seeing what happens. Then bring the pressure up to about 14-15. Any ideas would be very helpful.

BMmonteSS

Brian at TBI chips burned this prom for me.


You've got a pretty mean combo there, DIY tuning is going to be the only way to get it right. Other wise it's going to run like doodoo and be a wast of a good motor.

Ronny

iTrader: (1)

holley 670 i believe has 65 lbs injectors rated at 20 lbs FP. unless there are other inj's installed. may even be inadequate for your engine at WOT? that would worry me a lot. you need a WB! you say when its cold(you mean the coolant temp is cold) wont idle. there are choke commanded A/F in .bin as well as time out on them as well as A/F enrichment with low coolant temp's after choke times out. once you hit 165F you should be CL and at that time a aldl datalog will help you tune CL. unfortunately you have no way to diagnose OL(other than a WB) first start up. B4 i had a WB i tweeked those constants in .bin by sound of idle and looks of ext at talepipe for OL.

chevyz71man

I would love to buy a WB but thats alot of money, for that 300 I could just have it local dyno tuned at hitechmotorsports. I didnt think my motor was really anything wild, about 9.6 compression. Planed on trying to stuff a .480 lift cam in there this summer. I have no high end power, and I think this TB is really killing me. Been really thinking about a TPI computer and LT1 intake, but dont want to give up on the low end TBI can produce.

BronYrAur

iTrader: (1)

What's killing you is being able to tune for the Holley. You NEED to. What's the duration on the cam? Brian most likely didn't set up your injector constant right. Sounds like its rich around idle and low speeds. But I will guarantee you its lean (possibly dangerously lean) up top. 9psi just isn't enough fuel for that motor even if you're running the biggest injectors they offer. You best get yourself some tuning equipment and get that motor running right before you break it, that's my suggestion to you.

Even with an LT1 intake swap along with a TPI computer you WILL need to tune that computer too with your combo. Believe me, jump into tuning now.

BMmonteSS

It's not the throttle body thats killing you it's the chip.....now if I only had a dollar for every time I said that.

chevyz71man

Alright, well I have been looking into tuning. I guess I will have to go this route if I want to get it right. I am sure I am lean up high, probably why I lose alot of power. I guess I will start reading more on tuning and ask questions as I go. Thanks for the help.

89stroker

we're in the same boat buddy. hopefully u and i can get our stroker trucks to run how they're supposed to. Look into the EBL in the DIY prom board. i ordered one of them, and will hopefully have it in and installed by next week sometime.

Al Miles

I have one on a stock 350 truck crate motor with afterburn headers, 3" crossover, cat and cat back exhaust system with a Hyfire IV ignition. It runs rich at less than 2800 rpm and lean above 3200 rpm, even after half a dozen chips. So I called Holley, the information they gave me was 56# at 11 psi, 65# at 16 psi and 80# at 21 psi. I'm going to up my psi, but I want to install a shrader valve in the fuel line near the TBI. Has someone done this and can they post their method?

Ronny

iTrader: (1)

schroeder valver? i assume that is to allow a FP gauge temporary hookup? why not just add a permanenet FP gauge? i have one at FP regulator. seems one sets it and forgets it. i am running lean at WOT per WB so will up FP and see results. BUT WB02 sensor took a puke (again) so waiting for UPS to arrive..

Val Snyder

I have similar setup, not stroked,but try BPW of 122, If you want I will send fuel table+ Spark (if I can figure out how) 350 with 060 overbore,fairly ratty cam, flat tops 1.6 exhaust valves + shorty headers. C.R. figures at 10.25 if I recall correctly, always a question anymore, Good luck, Val

Val Snyder

Found engine notes,C.R. is 9.23, TB # 502-6 3210.. I paid 250 for a custom chip. Very rich on btm end, much chip burning to get close. By all means get the fuel pressure back up to around 14.5. I agree that the only way you will get a decent tune is to do it yourself, and that is gonna take a long while, at least it did for me. Use an ECM that is well documented, the 7747 is the most complete that I know of, Tho I don't know much. Good luck, Val

gsmarcano

If you run headers you have to get a heated O2 sensor or it will never get the correct reading to stop the "choke". and at low rpm it will resume the choke because the O2 sensor cools off too much.